Rotary drum stratifier for minerals



Qct. 14,-1947. EKREH R 2,428,974

ROTARY DRUM S TRATIFIER FOR MINERALS Filed Nov. 6, 1942 4 Sheets-Sheet lv I [maaflireher 1 IL/(M l Oct. 14, 1947. E, KREHER 2,428,974

- 7 ROTARY DRUM STRATIFIER FOR MII I1:'JRALS Filed Nov. 6., 1942 4Sheets-Sheet 2 ()Ct- 14, 1947. KREHER ROTARY DRUM STRATIFIER FORMINERALS Filed Nov. 6, 1942' 4 Sheets-Sheet 3 Fig.5

gum/Wm EmeatKreher E. KREHER ROTARY DRUM STRATIFIER FOR'MINERALS Oct.14, 1947,

Filed Nov. 6, 1942 4 Sheets-Sheet 4 fmaatKreher V Patented Oct. 14, 1947ROTARY DRUM s'rRA'rIFIER FOR MINERALS Ernest Kreher, Tampa, Fla.

Application November 6, 1942, Serial No. 464,723

6 Claims.

The primary object of the present invention is to provide a novel andefiicient system and. apparatus for the separation and collection ofgold, tin, and other valuable minerals occurring in their free state inalluvial or glacial deposits, in tailing deposits from miningoperations, or in quartz after it has been reduced to a size suitablefor handling by a centrifugal pump or by a water jet. The apparatus isparticularly adapted for the treatment of relatively finely dividedmaterial which can be delivered to the sump of the suction pipe of acentrifugal pump by dredges, by hydraulicking, or by any other form ofmining and conveying.

A further object of the invention is to utilize the varying effects ofthe pressure of flowing Water, of centrifugal force, and of gravitationupon materials of'different specific gravities as means to cause theremoval of the lighter particles from the heavier ones; This object isaccomplished by the provision of an inclined rotating shell or casing,enlarged beyond its inlet to reduce the speed of flow of a stream ofwater through the shell, and having means by which some of the materialsare carried upward to fall through the stream. Riffles" surrounding thestream act as barriers against which the heavier particles engageandfall downward through the space between the webs of the rifiles wherethere is substantially no longitudinal movement of the water. Theriffies have channels or passages between the outer edges of the websand the inner surface of the shell to permit the heavier particles togravitate down the inclined surface to a locked receptacle at thelowermost point of the shell.

The length and shape of the shell will be determined by the material tobe treated and by such considerations as cost, weight, ease oftransportation and of operation, and power requirements.

The speed of the stream of water will be regulated in accordance withthe length of the chamber and its rate of rotation to secure the desiredresults with the material being treated.

Since the force exerted by flowing water is proportional to the areaagainst which it engages, the same forcewill cause a greater travel ofaparticle of small mass than of a particle of equal area but ofgreater'mass, and the efiect of gravitation or of centrifugal force willcause a particle of greater mass to overcome the resistance of the waterin which it is suspended, more rapidly than a particle of equal area butof smaller mass will overcome the same resistance. Hence the lightermaterials will be carried through the separator more rapidly and withheavier metallic particles;

In Patent No. 2,217,687, granted October 15,

- spaces between the rifiles fill with matrix in so short a time ofoperation that the time lost in cleaning and collecting the metalrendered the apparatus relatively inefficient. In the present device,the matrix will not clog the spaces between the rifiies and cleaning isneeded only for repairs or replacements.

An important object of a modified form of the apparatus is the provisionof means for the discharge of the lighter'materials at the upper end ofthe inclined shell and for the continuous escape of the heaviestparticles at the lower end of the shell through an opening of a sizechosen in accordance with the quantity or the heavy, valuable materialspresent in the matrix being treated.

Another object is theprovision of a receptacle for gold or other highlyvaluable metals, which can be locked to prevent theft.

Other objects of the invention will be evident during the considerationof a preferred embodiment selected for purposes of illustration. It willof course be understood that the invention is not limited to the detailsof construction shown in the accompanying drawings, but many changes insize, form, proportions and structure may be made without departure fromthe invention as claimed.

In the drawings, Figure 1 is a side elevation of a preferred form of thedevice including a cylindrical separator, a centrifugal pump, and anelectric motor; Fig. 2 is a central longitudinal section On a scale fourtimes as large as that of Fig. 1, showing the construction of the endmembers of the separator and their connection with the inlet and outlettubes, the central part of the separator chamber being broken away; Fig.3 is a plan view of the structures shown in Fig. 1, on the same scale;Fig. 4 is a View, partly in elevation and partly in section, onapproximately the plane indicated by the line IVIV in Fig. 3; Fig. 5 isa transverse section through portions of the separator shell and of theintake end mem ber, looking towardthe right in Fig. 2 in the planesindicated by the line V-V; Fig. 6 is an end elevation of one of theriflles used in the separator shell; Fig. '7 is a diametral section ofthe same riflle looking toward the right in the plane indicated by theline VII-VII of Fig. 6; Fig. Bis a fragmentary view looking upward fromthe bottom of either Fig. 6 or Fig. 7; Fig. 9 is a fragmentary elevationwith parts broken away, of the operating lever, the brake drum flange,the stop pawl, and the adjustable end member of the brake band; Fig; 10is a side elevation of the" operating lever and the stop'pawl; Fig. 11is a section through the spring-pressed collar which holds the dischargepipe in its seat; Fig. 12 is a side elevation with parts in section ofthe shifter yoke of the friction clutch; Fig. 13 is a fragmen tarylongitudinal section of a modification of the structure shown in Fig. 2;Fig. 14 is a cross-section through the volute-shaped channel of Fig 13;and Fig. 15 is a plan View of the metal-collecting receptacle of Fig.14.

The central portion of the shell or casing of the separator is shown asa cylinder I having secured upon its ends flanged members 2 and 3. Tothe member 2 is secured the flange 4 formed at one end of the intakemember 5 which tapers down toward the inlet to a cylindrical bearingportion 6 within which is fitted the discharge end of the intake pipe 1,around which the portion 6 rotates within a bearing member 8. A suitablepacking 9 around the pipe is compressed in a stuffing box by the gland Iand the gland nut ll held in place by the lock nut 12. The intake pipe 1may extend into the member to any desired distance since the end of thepipe will not interfere with the flow of material into the separatorchamber. To the member 3 is secured the flange I3 of the outlet endmember M which tapers to a cylindrical bearing portion [5 mounted withina bearing member I6.

At the discharge end of the separator, the interior of the outer end ofthe outlet member I4 is made flush with the interior of the inner end ofthe discharge pipe ll which has a rotating bearing in the socket l8formed within the portion I5. A collar I9, best seen in Fig. 11, issecured to the pipe ll, preferably by one or more set screws 20. Withinthis collar are a plurality of sockets 2| for helical springs 22 whichbear at their outer ends against a flange 23 of a mem ber 24 securedupon a support 25. A stud 26 secured in the collar l9 projects outwardfor slidable engagement within a slot 21 formed within the rear edge ofthe member 24. The stud prevents rotation of the collar l9 and thus ofthe pipe H, while permitting the pipe to be held within the rotatingsocket l8 by the thrust of the springs 22.

A liquid-tight joint between the pipe I! and the member I4 is providedby a packing 9 in a stufling box having a gland l0, nut H, and lockingnut l2 such as are used with the pipe 1.

Within the shell I, throughout substantially its entire length, are aplurality of riflies 28 each consisting of a flat, annular web mountedradially of the axis of rotation of the shell. From each Web project aplurality of vanes 29 each having one wing 39 set more or less radiallyof the web and at right angles thereto and having a second wing 3| setsubstantially at right angles to the web and to the wing 39. The wings31 extend across the outer edge of the annulus 28 to space it an eighthof an inch, more or less, from the interior surface of the cylindricalcasing I as best seen in Figs. 5, 6, and 14. Six such vanes are shown inthese figures, but obviously the number used is a matter of choice orconvenience. On the outer end of one of the vanes on each riflle, aV-shaped point 32 will be formed to enter a corresponding recess 33either in the next adjacent rifile plate toward the inlet or in one ofthe projections 34 formed on the inner periphery of the member 2 againstwhich the outer ends of the endvanes of the series abut when theassembly of riflles is installed within the cylinder I. A plurality ofscrews 35 extending through the flange I3 are arranged to bear againstthe side of the outermost riffle to clamp the whole group of riffiestogether and force the lowermost riflie against the projections 35, thuspreventing the group from turning within the cylindrical shell. Exceptfor the projecting lugs 34, the interior of the member 2 issubstantially flush with the inner surface of the cylindrical shell I,so that material sliding downward beneath the lowermost riffle webbetween the wings 3| may pass freely through the spaces between the lugs34 into the tapered end member 5.

Formed-upon or secured to the central portion of the end member 5 is abrake drum 35 upon a side face of which is secured a bevel gear 31 inmesh with a smaller bevel gear 38 on a shaft 39. A pulley t5, driven bya belt 4! from an electric motor 42 and running freely on the shaft 39may be connected to the shaft to cause rotation of the gears by the useof any suitable clutch, such as the expanding ring type of frictionclutch shown at 43 in Fig. 3. The shifter yoke 44 for the clutch shownin Figs. 3 and 12 as carried by a sliding plate 55 operated by a pushrod 46 is caused to move into and out of operative position by a leverll to which the rod 45 is pivoted at the lowermost end of the lever. Thelever 41 is pivoted on a support 58 closely adjacent to a flange '59 onthe brake drum 36. The plate 45 may also carry a link '35 to operate aswitch 42 controlling the motor 42.

The lever 47 is provided on the edge adjacent to the brake drum with alug 59 engaged on opposite faces by the wings of a nut 5|. This nut isadjustable longitudinally of the threaded end of a rod 52 pivoted at 53on one end of the brake band 54. After adjustment of the nut, it issecured upon the lug by a pivot 55.

The other end of the brake band is secured by links 56 to the member 48.A stop pawl 51 is pivoted beside the lever M on the member 48 with thepawl 1ying in the plane of the flange 49. A notch 58 is cut in theperiphery of the flange and provided with a cushion, which may be formedof leather strips 59 glued together and. bolted upon the flange at theend of the notch for engagement with the end of the pawl 51. A bolt 69has a terminal yoke 6| pivoted at 62 on the pawl, the shank of the boltbeing surrounded by a helical spring 53. A lug 54 projects laterallyfrom the rear edge of the lever 41 and has a perforation through whichthe bolt 69 passes. A nut 55 On the opposite face of the lug from thespring holds the bolt and the pawl in place with the ends of the springengaging the yoke El and the lug 6 5.

As the lever 41 is pushed forward from the broken line inoperativeposition of Fig. 9 toward the brake drum, it acts to perform severaloperations in sequence: first, it pulls on the rod 46 to cause the plate45 to slide to open the switch 62 of the motor and to move the shifteryoke M to disengage the clutch 43. The separator through its inertiawill continue to revolve for awhile after the clutch is released and theoperator at the proper time will move the lever farther forward to causea downward pull on the nut 5! to tighten the brake band and thus to slowdown the rotation of the shell. Forward movement of the lever will bringthe pawl into contact with the rim of the flange 49 but it can bewithdrawn if the speed is too great. As the notch 58 is seen approachingthe pawl, the lever can be moved forward strongly to complete the actionof the brake band just as the pawl engages the end of the notch, thisbeing the positionin which the recep- T tacle 6T or? BB is apth'elbwermo'st: point anther. separator-assembly; The. spring isicompressed:as the: lever moves to itsextreme forward posiition withoutcorresponding movement of: the pawl;

This sequence of operations releases? the sepa:-= rator: from. thedriving forceofithe'motor; applies. agradually increasingfrictiorr ontheibrakeidrum; and finally stops the shell at a definite point,- which"i's th'e position shown. in: Figs; 1:. to.- 5,'. 13 and le.

The motor 4 2: is connected by belts 6a with the: drive shaft 110 of acentrifugal ump 11 having: an: intake pipe indicate at l2 and a:dischargenozzle at 13. The intake pipe 12 is of a len'gth'. to connectthe pump with" a sump or tankptovidedto" receive'the matrix to bevtreated and to: receive material discharged from: the shell; when; ithas been stopped, as" for the removal. an'd'replacement of a receptacle,

As seen in Figs; 1- and 3,.the discharge; nozzle 13 is connected withthe'pipe 1 by a flexible hosei 1-4 01 an suitable length. While it isshown in:

these figures short, it will" b'e' evidentthat the' hose serves merelythe necessary connection: between the pump or water jet. at the sump andthe separator which may be ate; considerable distance' away for greaterconvenience in use;

Thematerial to be treatedby' the present: separator will be of sizes nogreater than can pass. readily through' the intake pipe 12-, largerpiecesv being removed by screenson other apparatus; not shown, to'obviate" any danger of. clogging any of the assages in the a paratus.

The stream. (if water carrying: the mixture of minerals suspensionwillbe driventhrough the pipe 7 into the upwardly inclined'rot'ating sepa--rator whose shell has a diameter greater: than that of the pipe. Thevelocity of the stream. of water will be reducedbecause o'f'this largerdiameter of the shell, while the riffles will. prevent a free flow ofthe water: along the outerportio'n of thechamber. The greatest velocitywill be maintained substantially along" the axis of. rotation.

The material will consist of'parti'cles" differing: in specific gravity.With equal-pressure of the flowing water, the lighter portions willbe'carried faster and farther thanthe heavier ones, but the speed offlowwill be so regulated thatthe heavier materials to be retained will dropdown at the reduced speed'of'flow within the intake member 5 or betweenthe webs 28 of the riffles where there is substantially. no forward;movement of the water.

The centrifugal force caused by the rotation o the shell will exert agreater outward pressure of the heavier particles than of the lighterones, toward thewall of the casing. The lighter particles suspended inthe central rapid current will be very little affected by thecentrifugal force.

In locations where clay or the like causes the matrix to adhere inlumps, one or more breaker bars I6- may be secured to the wings 30 ofthe riffies as indicated in Fig. 6, to extend across the middle of thestream to be engaged by the lumps to cause them to disintegrate.Material between the webs of the riifles encountering the Wings 38 willbe carried upward and dropped again into the top of the flowing stream.The repeated-tumbling over of the matrix assists in washing and scouringfrom the metallic particles films or incrustations of lightermaterialsby the attrition of the individual bits orp'iecesagainst eachother and against the apparatus.

The "lighter'portionswill .travelzupwardandloutewardiataaratersubstantially'in proportion to thei'r weight after deducting. thweight of the water; they displace: The heaviest particles falling and.being: thrown by centrifugal force against the in. terionsurface of theshell: will. slide. downward: along the inclined surface, passingthrough the: spaces: between; theiwingss'tl' and: between. the:outeredgesot the rifilewebs-: and the inner surface" of the? shell;

A' steady andfree flow of 'the' materials may be assisted by the:ercussive impacts of .elekztro-mag neti'c vibratorsindicated at 1 5- inFigs; 1 and; 13.. The angle of inclination can be reduced if thenretalliccasing is vibrated. to eliminate friction betweenthematerial'and: the surface along whichit musttravel'. With: such vibrators in use,the possibility of clogging of the spaces between thewebs of therifil'es is materially reduced.

The heaviest particles, sliding downward along the inclined innersurface of the shell, will finally reach the lowermo'st end and willenter the widest portion of. the member'5. In Figs. 2 and 13, theinterior of the member 5 is shown as' expanding or widening toward theleft from the flange 4' to a channel 66 which: maybe formed as a volutein section. as best seen in Fig. 14, with the receptacle' 61 at thegreatestdi'stance of the curve from the axis of rotation, or the channelmay be sub-- stantially concentric with the axis as shown in Figs.= 2and 5, with the receptacle 68 at the end of a lateral pocket.

In Fig. 2, the member 5 is shown as. provided on its interior with aprotector ring 1.5 whichv may consist of one or more pieces secured tothe; member 5 by screws TI. This ring extendsiforward. beyond thechannel to direct the stream of water into the eylindricalshell I. toprevent the. stream. from? directly entering the channel. to: washout'materi'al that has gravitated into it, while if. anysuchmaterialshould be carried upward. and fall from the receptacle, it would engagethe outer surface of t e .r and s be prevented from falling into thestream.

The structure shown in Fig. 13 omits the protector ring, since, with thevolute' channel, the centrifugal force of' rotation at a proper speedwill be sufficient to hold the heavy metal in the receptacle.

Inboth Fig. 2 and Fig. 13, a padlock 18 is shown in a stud 19 secured.in the member 5' to prevent sidewise' outward movement ofthe receptacle6'! or '68: each of which has an ear'80 to receive the stud asv thereceptacle is slid into position between the lugs 8| and 82. The frontedge of the rim of the receptacle is beveled at 83 to engage within acorrespondingly undercut notch in the member 5. The lug M has a beveledupper. surface tobe engaged by the tapering smaller end of thereceptacle while the lug 82 has a set screw .84 to thrust the receptaclelongitudinally and upward to bring the smoothly ground upper surfaceinto liquid-tight contact with the smooth lower surface surrounding theoutlet of the chanopening 86 at the outermost point radially from theaxis of rotation for the continuous escape of water and for the escapeof any minerals that may gravitate to this outlet. A metallic hood 8'!surrounds the shell I at its lower end and the end member near thechannel 66 to receive the concentrate discharged from the opening 86. Receptacles will be provided having openings of different sizes from whichto select the proper outlet to agree with the rate of concentration,which will be dependent upon the relative quality of metal in thematrix, on the proportion of solids to water in the flowing stream, onthe speed of the stream, and on other factors.

The apparatus will thus provide a continuously operating separator fromwhich the lighter materials will be discharged at the upper end and theheavier materials at the lower end. While some of the lighter mineralsmay accompany the heavier minerals to the receptacle, there is no forceacting on the heavier minerals that can discharge them at the upper endonce they have dropped from the flowing stream, unless they are embeddedin or attached to lighter bodies of which they form a minor portion.

Lugs 88 shown in Fig. 14 serve as a pedestal to support the receptaclewhen it is removed and set down on a fiat surface and also provide aplace to be struck with a hammer to dislodge the receptacle when takingit ofi the shell.

It will be understood that the details of construction shown anddescribed are purely illustrative and the invention is to be construedbroadly within the full scope and meaning of the claims.

I claim:

1. A separator for minerals difiering in specific gravities comprising aseparator chamber having an inlet member, a central portion of greaterdiameter than that of the inlet member, and an outlet member, the inletand outlet members being mounted for rotation in bearings of which thebearing for the outletmember is the higher, a plurality of annularriilles having their outer edges separated from the inner surface of thecentral portion and theirinner edges surrounding the central openingsubstantially concentric with the axis of rotation of the chamber, meansfor forcing a stream of Water having finely divided minerals insuspension therein through the inlet member into the separator chamber,means for rotating the separator chamber, and means carried by arotating member to engage material between the rifiles and to carry itupward to the upper portion of the flowing stream;

2. A separator for a mixture of finely divided minerals differing inspecific gravities which comprises means providing an inlet passagewayfor a stream of Water carrying the mixture in 1 suspension, an upwardlyinclined shell of larger internal diameter than that of the inlet,whereby to cause the speed of flow of the stream to be lessened, aplurality of annular riflles having webs extending transversely of theshell and having portions of their outer edges spaced from the interiorof the shell, the webs having wings extending into the spaces betweenthe Webs, and means for rotating the rifiles around the stream, wherebymaterial engaged by the wings will be moved sidewise from below thestream, upward at one side of the stream, and discharged into thestream,,and whereby heavier particles may slide downward within theinclined shell.

3. A mineral separator comprising a rotating shell havingan end memberat its lower end,

8 means within the shell permitting gravitation of heavy minerals downthe inner surface of the shell, the end member being provided with achannel to receive material from the shell, the bottom of the channelgradually increasing in radial distance from the axis of rotation of theshell, and a receptacle at the point of greatest distance of the bottomof the channel from the axis,

4. A structure as in claim 3 in which the receptacle is provided with anopening for the escape of material entering the receptacle, and in whichthere is a hood surrounding the locus of travel of the receptacle toreceive material leaving the opening,

5. A separator fOr minerals comprising a tubular conveyor for flowingwater, including an intake portion and an inclined rotary separatorchamber, a plurality of annular riflies mounted within the chambertransversely of its axis of rotation and having portions of theirexterior peripheries separated from the inner wall of the chamber, eachriflle having a central aperture substantially concentric with the axisof rotation of the chamber and of greater area than that of the intakeportion whereby to reduce the rate of flow of water through the chamber,means for rotating the chamber, and means for forcing water carryingminerals of difierent specific gravities in suspension upward throughthe tubular conveyor, the arrangement being such that heavier particlesof the suspended materials at the slower rate of flow within the chamberwill engage the baffies to arrest forward movement.

6. A mineral separator comprising a substantially cylindrical shellhaving an annular end member secured upon the lower end thereof, aplurality of riflles having projecting portions engaging the innersurface of the shell to space the outer edges of the rifiles from theshell to provide passageways between the riifles and the shell, therifiles being slidable longitudinally of the shell for assembly inspaced relation with their webs radial to the shell, the said end memberhaving lugs projecting inward for engagement with the lowermost rifiieof the assembly and having the inner edge of the annular membersubstantially flush with the inner surface of the shell in spacesbetween the lugs, and means for clamping the riffies removably withinthe shell for rotation therewith,

ERNEST KREHER.

REFERENCES CITED The following references are'of record in the file ofthis patent:

UNITED STATES PATENTS- Number Name Date 888,767 Trottier May 26, 1908969,591 Abeel Sept. 6, 1918 987,677 Hogan Mar. 21, 1911 1,027,952 WickMay 28, 1912 1,034,252 Lewis July 30, 1912 1,034,259 Lewis July 30, 19121,064.459 Du Pont June 10, 1913 1,362,448 Sudlow Dec. 14, 1920 1,660,551Garson Feb. 28, 1928 1,673,675 Hanciau June 12, 1928 1,930,075 BentleyOct. 10, 1933 1,983,968 Clark Dec. 11, 1934 FOREIGN PATENTS NumberCountry Date 131,969 Germany June 28, 1902

